Why does one of you kill his brother? Why did you not say, “May Allah bless you?” Do ghusl for it.

[Silsilatus-Saheeha (6/149)

Ibn Abdul-Barr rahimahullah in al-Istadhkaar: ” His statement sallahu alayhi wa salam: “Why did you not say, “May Allah bless you?” indicates that the one who likes something and says: “Tabarakallahu Ahsanul Khaliqeen, Allahumma Baarik fihi” or the likes of this, then he will not harm it [the thing he likes] inshallah”

And he said rahimahullah in at-Tahmeed: “at-Tabreek is for a person to say: Allahummah Baarik fihi” or the likes of this. It was said that at-Tabreek is to say: “Tabarakallahu Ahsanul-Khaliqeen Allahumma Baarik fihi”
This statement: “Tabarakallahu Ahsanul-Khaliqeen Allahumma Baarik fihi” was mentioned by more than one scholar of the past, but I did not find any proof for it.

Ibn al-Qayyim said in Zaad al-Ma’ad: “if the one who gives the evil eye fears harm due to his eye, then let him remove the harm by his statement: Allahumma Baarik ‘alahi as the Prophet sallahu alayhi wa salam said to ‘Aamir ibn Rabi’ah when he saw Sahal ibn Hunaif. He said: Why did you not say, “May Allah bless you…”